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Titolo:
Influence of acoustic masking noise in fMRI of the auditory cortex during phonetic discrimination
Autore:
Shah, NJ; Jancke, L; Grosse-Ruyken, ML; Muller-Gartner, HW;
Indirizzi:
Res Ctr Julich, Inst Med, D-52425 Julich, Germany Res Ctr Julich Julich Germany D-52425 Inst Med, D-52425 Julich, Germany
Titolo Testata:
JMRI-JOURNAL OF MAGNETIC RESONANCE IMAGING
fascicolo: 1, volume: 9, anno: 1999,
pagine: 19 - 25
SICI:
1053-1807(199901)9:1<19:IOAMNI>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
TIME-SERIES; BRAIN;
Keywords:
cerebral blood flow; auditory cortex; acoustic noise; gradient noise; functional magnetic resonance imaging;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Citazioni:
18
Recensione:
Indirizzi per estratti:
Indirizzo: Shah, NJ Res Ctr Julich, Inst Med, Leo Brandt Str, D-52425 Julich, GermanyRes Ctr Julich Leo Brandt Str Julich Germany D-52425 ch, Germany
Citazione:
N.J. Shah et al., "Influence of acoustic masking noise in fMRI of the auditory cortex during phonetic discrimination", J MAGN R I, 9(1), 1999, pp. 19-25

Abstract

The application of functional magnetic resonance imaging (fMRI) to study activation of auditory cortex suffers from one significant confounding factor, namely, that of the acoustic noise generated by the gradient system, which is an integral part of the imaging process, Earlier work has shown that it is indeed possible to distinguish cortical activation resulting from presentation of auditory stimuli despite the presence of background noise fromthe gradient system, The influence of acoustic noise from the gradient system of the MRI scanner on the blood oxygen level-dependent (BOLD) response during functional activation of the auditory cortex has been investigated in six healthy subjects with no hearing difficulties. Experiments were performed using gradient-echo echoplanar imaging (EPI) and a verbal, auditory discrimination paradigm, presented in a block-wise manner, in which carefullyaligned consonant-vowel syllables were presented at a rate of 1 Hz, For each volunteer the experiment was repeated three times with all parameters fixed, except slice number, which was 4, 16, or 64, The positioning of the central four slices in each experiment was common, Thus, the fraction of TR during which the stimulus is on but no imaging is being performed, varies from almost zero, in the case of 64 slices, to over 8 seconds, in the case offour slices. Only the central four slices were of interest; additional slices simply generated acoustic noise and were discarded, During the four-slice experiment, all subjects showed a robust BOLD response in the superior temporal gyrus covering the primary and secondary auditory cortex. The spatial extent and the z-scores of the activated regions decreased with longer duration of gradient noise from the scanner. For a phonetic discrimination task, the results indicate that presentation of the stimulus during periods free from scanner noise leads to a more pronounced BOLD response, J, Magn, Reson, imaging 1999;9:19-25, (C) 1999 Wiley-Liss, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/03/20 alle ore 19:55:36